/Engine/Source/Editor/UnrealEd/Public/SkinWeightsUtilities.h
This function reimport all skin weights profile for a specified LOD. Return true if the weights are successfully updates. If it return false, nothing in the skeletal skin weights was modified.
static bool ReimportAlternateSkinWeight ( [USkeletalMesh](API\Runtime\Engine\Engine\USkeletalMesh) * SkeletalMesh, int32 TargetLODIndex )